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More about
Honey Bees
Reproduction
and Development
The queen controls the sex of her
offspring. When an egg passes from her ovary to her oviduct, the queen
determines whether the egg is fertilized with sperm from the spermatheca. A
fertilized egg develops into a female honey bee, either worker or queen, and an
unfertilized egg becomes a male honey bee, or drone. The queen lays
the eggs that will develop into more queens in specially constructed
downward-pointing, peanut-shaped cells, in which the egg adheres to the ceiling.
These cells are filled with royal jelly to keep the larvae from falling and to
feed them.
Worker bees are raised in the multi-purpose,
horizontally arranged cells of the comb. Future workers receive royal jelly only
during the first two days, compared to future queens, who are fed royal jelly
throughout their larval life. This difference accounts for the great variation
in anatomy and function between adult workers and queens. On average, the
development of the queen from egg to adult requires 16 days; that of the worker,
21 days; and that of the drone, 24 days.
Activities
Field honey bees collect flower nectar. On
entering the hive with a full honey sac, which is an enlargement of the
esophagus, the field bee regurgitates the contents into the mouth of a young
worker, called the house, or nurse, bee. The house bee deposits the nectar in a
cell and carries out the tasks necessary to convert the nectar to honey. When
the honey is fully ripened, the cell is sealed with an airtight wax capping.
Both old and young workers are required to store the winter supplies of honey.
Pollen is carried into the nest or hive on the
hind legs of the field bees and placed directly in the cells. The pollen of a
given load is derived mostly from plants of one species, which accounts for the
honey bee's outstanding role as pollinator. If it flew from one flower species
to another, it would not be effective in the transfer of pollen, but by
confining its visits on a given trip to the blossoms of a single species, it
provides the cross-pollination required in many varieties of plants.
Communication
An amazing symbolic communication system exists
among honey bees. In studies of bees begun in the early 1900s, the Austrian
zoologist Karl von Frisch determined many of the details of their means of
communication. In a classic paper published in 1923, von Frisch described how
after a field bee discovers a new source of food, such as a field in bloom, she
fills her honey sac with nectar, returns to the nest or hive, and performs a
vigorous but highly standardized dance. If the new source of food is within
about 90 m (about 295 ft) of the nest or hive, the bee performs a circular
dance, first moving about 2 cm (about .75 in) or more, and then circling in the
opposite direction. Numerous bees in the nest or hive closely follow the dancer,
imitating her movements. During this ceremony, the other workers scent the
fragrance of the flowers from which the dancer collected the nectar. Having
learned that food is not far from the nest or hive, and what it smells like, the
other bees leave the nest or hive and fly in widening circles until they find
the source.
If the new source of nectar or pollen is
farther away, the discoverer performs a more elaborate dance characterized by
intermittent movement across the diameter of the circle and constant, vigorous
wagging of her abdomen. Every movement of this dance seems to have significance.
The number of times the bee circles during a given interval informs the other
bees how far to fly for the food. Movement across the diameter in a straight run
indicates the direction of the food source. If the straight run is upward, the
source is directly toward the sun. Should the straight run be downward, it
signifies that the bees may reach the food by flying with their backs to the
sun. In the event the straight run veers off at an angle to the vertical,
the bees must follow a course to the right or left of the sun at the same angle
that the straight run deviates from the vertical.
Bees under observation in a glass hive demonstrate their instructions so clearly
that it is possible for trained observers to understand the directions given by
the dancers. Certain aspects of the dance language, such as how attendant bees
perceive the motion of dancers in the total darkness of the nest or hive, are
still unknown. The dance language is an important survival strategy that has
helped the honey bee in its success as a species.
Problems of
Survival
Honey bees are subject to various
diseases and parasites. American and European foulbrood are two widespread
contagious bacterial diseases that attack bee larvae. A protozoan parasite,
Nosema, and a virus cause dysentery and paralysis in adult bees. Two species of
blood-sucking parasitic mites are particularly troublesome for beekeepers and
are currently affecting wild honey bees worldwide.
The honey bee tracheal mite lives in the breathing tubes of adult bees; the
varroa mite lives on the outside of larvae and adults. These mites have killed
tens of thousands of honey bee colonies in North America during the past ten
years. Scientific breeding programs are attempting to develop tolerant strains
of domestic honey bees to replace the mite-susceptible ones currently used.
Tracheal mite infestations can be reduced by fumigation of the hive with menthol
fumes. Varroa mites are controlled with a miticide or, in some European
countries, with fumes of formic acid. Certain hive management techniques also
can reduce infestations.
Many other animals prey upon
individual honey bees, which may sometimes weaken colonies. Examples are cane
toads and bee eaters (birds), which pick off foragers near the colony entrance;
robber flies, which take individual foragers as they visit flowers; and hornets
and bee wolves (wasps), which may enter the nest or hive and steal larvae. Bears
have an insatiable appetite for honey and bee larvae and may destroy many nests
or hives in a single raid.
Honey bee colonies used in
commercial pollination and those kept in urban areas are exposed to pesticides,
fungicides, fertilizers, and other agricultural chemicals and are frequently
poisoned by accident. This is a major concern of modern beekeepers.
Importance
Honey bees have become the primary source of pollination for approximately
one-fourth of all crops produced in the United States and some other countries.
The value of the crops that rely on such pollination has been estimated as high
as billion annually in the United States. Examples of fruit crops that rely on
honey bees are almonds, apples, apricots, avocados, blackberries, blueberries,
cantaloupes, cherries, cranberries, cucumbers, pears, raspberries, strawberries
and watermelons. The seeds of many vegetables are also produced with honey bee
pollination; examples include alfalfa, asparagus, broccoli, brussel sprouts,
cabbage, carrots, clover, cotton, cucumbers, onions, radishes, squash, sweet
clover, and turnips.
Many species of wild
pollinators have disappeared from the land as their habitats have been destroyed
or altered by humans. The honey bee has taken over as pollinator of many of the
wild plants that remain; its ecological value in this regard is tremendous.
Honey bees are the sole source
of honey and beeswax, a fine wax with unusual qualities. Honey bees also produce
propolis, a gummy substance made from tree sap that has antibacterial
properties, and royal jelly and pollen for human consumption. Honey bee venom is
extracted for the production of antivenom therapy and is being investigated as a
treatment for several serious diseases of the muscles, connective tissue, and
immune system, including multiple sclerosis and arthritis.
Scientific
classification
Honey bees comprise
the genus Apis in the family Apidae, order Hymenoptera. The European honey bee
is classified as Apis mellifera, the Indian honey bee is A. cerana,
Koschevnikov's honey bee is A. koschevnikovi, the dwarf honey bee is A. florea,
the andreniform dwarf honey bee is A. andreniformis, the giant honey bee is A.
dorsata, and the mountain giant honey bee is A. laboriosa. The Italian race of
the European honey bee is A. m. ligustica, the Carniolan race is A. m. carnica,
and the Caucasian race is A. m. causcasia.
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